The present invention is directed to a refrigerant coupling which permits rapid connection of refrigerant lines under pressure without the use of tools with a minimum of refrigerant loss from or entry of air into the system during connection, operation or storage. It is particularly useful with portable split air-conditioning systems having an indoor unit with an evaporator coil and compressor and outside unit having a condensing coil. These types of units are particularly popular in Europe and Asia as the indoor unit, which is more expensive than the outside unit, may be moved from room to room thus permitting selective cooling of an apartment or house on a room by room basis thus avoiding the necessity of incurring the expense of central air-conditioning. One such system is sold under the name Argo by Filiberti S.p.A., Via Cadoma, 22-21044 Cavaria (VA) Italy.
Since the indoor unit of any such system may be frequently moved from room to room, it is desirable that it be used with a coupling designed to be rapidly and easily disconnected and reconnected to an outside unit and with a minimum of air entering the system and with a minimum of refrigerant loss from either unit during any such disconnecting and reconnecting operation even though the air-conditioning refrigerant in one or both such units may be at an elevated pressure at the time of such disconnecting or reconnecting operation. Furthermore, it is desirable that each connecting and disconnecting operation is able to be accomplished without the use of tools.
Accordingly, it is an object of the present invention to provide a quick connect refrigerant coupling capable of connecting portions of a refrigerant transport system which are maintained under pressure with a minimal loss of refrigerant or entry of air into the system and to do so without the necessity of using tools in making such connection or disconnection.
It is well known that air-conditioning refrigerants such as Freon 22 can penetrate and effuse through elastomeric seals. Accordingly, it is a further object of the present invention to provide a refrigerant coupling which may be rapidly connected as aforesaid and which is provided with a final seal which minimizes effusion of refrigerant. Under one embodiment a metal to metal seal is provided while under another embodiment an effusion resistant seal is provided.
In the portable units such as the Argo unit referenced heretofore, it is necessary to have two fluid flow lines, one of which directs compressed refrigerant in gaseous form from the compressor of the in-house unit to the condensing coil of the outside unit and the other of which directs refrigerant in liquid form from the outside unit to the inside unit. It is desirable to provide a single coupling which joins together opposing ends of both sets of fluid flow lines. Accordingly, it is a further object of the present invention to provide a quick connect refrigerant coupling housing two valves in parallel for connecting together opposing ends of two fluid flow lines in one operation and to do so without significant loss of either liquid or gaseous refrigerant or significant entry of air into the system.
When the in-house unit is disconnected from the outside unit, valves contained within the respective ends to be joined together will be closed and maintained in a sealed relationship to prevent escape of refrigerant. The valves will be under significant pressure, on the order of 125 psi to 200 psi depending upon the ambient temperature. When the opposing ends of the coupling are joined together, they become sealingly engaged to one another prior to opening the valves to the flow of refrigerant. Thereafter, the cams on the coupling are actuated to cause the valves to open thereby permitting the flow of the refrigerant through the lines.
Under one embodiment an elastomeric O-ring positioned in an annular groove of a valve stem having an enlarged head engages a tapered metal surface of a cooperating annular sleeve to seal the refrigerant in the line. When opposing ends of the lines are joined together the flow of the refrigerant through the lines under pressure has a tendency to cause the O-ring to blow out of the annular groove of the enlarged head of the stem valve. Under one embodiment of the present invention, the stem valve is provided with a design which permits an annular portion thereof to be deformed following positioning of the O-ring in the annular groove to thereby squeeze and lock the O-ring tightly in the annular groove thereby preventing the possibility of blow out of the O-ring upon opening of the valve to the refrigerant under pressure. Accordingly, it is another object of the present invention to provide a new method of forming a valve stem and a new design of valve stem which prevents unintended blow out of the O-ring from the annular groove.
Other objects and advantages of the present invention will be readily apparent from the detailed description of the invention.